Redirecting input and output for multiple computers

ABSTRACT

Apparatus, methods, and systems provide for remote management of a set of local computers by transferring screen frames produced by the local computer for viewing at a remote computer. A redirection module captures and transmits video signals from a local computer through over a network, such as the Internet, to a remote computer where the remote computer produces a display that contains the screen frames being transferred. The module is configured for use with and installation within a keyboard, video, and mouse switch configured for receiving the module. The redirection module is further configured for use with and installation on a server-blade to allow remote management of the server-blade.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.10/926,241 filed Aug. 25, 2004 now U.S. Pat. No. 7,519,749, which isexpressly incorporated herein by reference.

This application is related to U.S. patent application Ser. No.12/395,015, filed Feb. 27, 2009, entitled “Redirecting Input and Outputfor Multiple Computers”; and U.S. patent application Ser. No.12/395,022, filed Feb. 27, 2009, entitled “Redirecting Input and Outputfor Multiple Computers”.

This application is also related to U.S. Pat. No. 6,825,846, entitled“System and Methods for Capturing Screen Displays from a Host ComputingSystem for Display at a Remote Terminal,” filed Dec. 10, 2001; U.S. Pat.No. 7,260,624, entitled “Systems and Methods for EstablishingInteraction Between a Local Computer and a Remote Computer,” filed Sep.20, 2002; U.S. Pat. No. 6,894,906, entitled “Housing For In-Line Video,Keyboard and Mouse Remote Management Unit,” filed Jun. 14, 2004; andU.S. Pat. No. 7,454,490, entitled “In-Line Video, Keyboard and MouseRemote Management Unit,” filed Jun. 14, 2004, which are eachincorporated by reference herein.

BACKGROUND OF THE INVENTION

Computers are often linked together through networks to allow theresources of a computer at one location to be used by a computer and enduser at another location. It is often necessary to manage activities ofa computer or determine the relative health of a computer system byviewing screen display information and/or interacting with the computerthrough user input devices. This is especially true for servers whoseresources are utilized by many individual client computers, such aswithin a corporate network or the Internet. For many conventionalsystems, the technician or other user who needs to view the screendisplays and interact with the computer being managed is required to bephysically located at the site of the computer. However, it is notalways feasible for a technician or other user to be physically present.

For example, a system administrator of a corporate network is present atone location, but the computers of the corporate network may be spreadaround the globe. To effectively manage the computers of the corporatenetwork, the system administrator must be able to effectively monitormany or all of the computers of the network contemporaneously. Becausethe system administrator cannot be physically present at each computerto be managed at the same time, effective management of the computers ifthe network becomes very difficult if not impossible. As a result,costly additional human resources are required to improve management ofthe computers.

Present solutions to providing remote management are a service under theoperating system or a software application such as PC ANYWHERE fromSYMANTEC CORPORATION. However, because these present solutions aresoftware based, the operating system must be operational with allservices loaded to allow the remote monitoring to occur. Therefore,configuration and boot-up screens such as those provided by a BIOS arenot made available to the remote location. For this reason, utilizationof a hardware-based device is desirable.

Hardware based devices for providing remote management are alsoavailable. U.S. Pat. No. 6,825,846, entitled “System and Methods forCapturing Screen Displays from a Host Computing System for Display at aRemote Terminal” and assigned to AMERICAN MEGATRENDS, INC., describeshardware used to send and receive keyboard, video, and mouse input datato and from a remote computer. Similarly, U.S. Pat. No. 7,260,624,entitled “Systems and Methods for Establishing Interaction Between aLocal Computer and a Remote Computer” and assigned to AMERICANMEGATRENDS, INC., describes an external device, which when connected toa local computer and to a network, may be used to send and receivekeyboard, video, and mouse input data to and from a remote computer. Inorder to remotely manage a computer using these hardware based devices,each computer to be remotely managed is connected to a remote computerthrough a network using either an internal card, or an external remotemanagement device. This can become cumbersome when there are many localcomputers for which it is desirable to remotely monitor and manage.

An alternative is to connect each of the local computers to a keyboard,video, and mouse (“KVM”) device. The KVM device must then be connectedto a remote computer via an external remote management device connectedto the network. While effective, doing so increases the number of cablesand connectors from the local computer to the remote computer,increasing the possibility for signal degradation as well as increasingthe general clutter around the KVM since the cables and external remotemanagement device occupies space. It is with respect to theseconsiderations and others that the present invention has been made.

SUMMARY OF THE INVENTION

Aspects of the present invention address these problems and others byproviding a KVM redirection module for establishing interaction betweenone of a plurality of local computers and a remote computer. Theredirection module includes a printed circuit board that has aninterface connector, a frame grabber, a network interface device with anetwork connector, and a processing device. The interface connector isdisposed at a one edge of the printed circuit board and is configured tointerface with a mating connector on a KVM switch. The redirectionmodule is configured to receive video signals from a selected localcomputer of the plurality of local computers through the KVM switchmating connector. The frame grabber on the printed circuit board grabsscreen frames from the video signals to create screen frame data. Theprocessing device is configured to provide the screen frame data to thenetwork interface device for distribution across a network.

Another aspect of the invention is a KVM switch for allowing control ofa plurality of local computers from a remote computer. The switchincludes a printed circuit board having at least one internal connectorfor connection to a KVM redirection module, and a housing that enclosesthe printed circuit board and internal connector. Each internalconnector is configured to provide video signal data from a localcomputer to a connected KVM redirection module. The housing of theswitch contains at least one opening opposite the internal connectorsfor receiving a KVM redirection module. Additionally, the switchcontains a plurality of keyboard, video, and mouse input connectorscorresponding to the plurality of local computers. These inputconnectors are electrically connected to the printed circuit board andare accessible externally from the housing.

Yet another aspect is a system for allowing control of a plurality oflocal computers from a remote computer. The system includes a firstprinted circuit board having an internal connector, a KVM redirectionmodule comprising a second printed circuit board having an interfaceconnector connected to the internal connector of the first printedcircuit board, and a housing encompassing the two printed circuitboards. The second printed circuit board also has a frame grabber, anetwork interface device with a network connector, and a processingdevice. The second printed circuit board is configured to receive videosignals from a local computer through the internal connector of thefirst printed circuit board. The frame grabber on the second printedcircuit board grabs screen frames from the video signals to createscreen frame data. The processing device is configured to provide thescreen frame data to the network interface device for distributionacross a network.

The housing contains at least one opening opposite each internalconnector for receiving a KVM redirection module. Additionally, thesystem contains a plurality of keyboard, video, and mouse inputconnectors corresponding to the plurality of local computers. Theseinput connectors are electrically connected to the first printed circuitboard and are accessible externally from the housing. Video and inputsignals from the plurality of local computers flows into these inputconnectors, through the first printed circuit board, through the secondprinted circuit board where they are processed, and out the networkconnector to the remote computer via the network.

Another aspect of the invention is a KVM redirection module forestablishing interaction between a plurality of local computers and aremote computer. The redirection module includes a printed circuit boardthat has an interface connector, a frame grabber, a network interfacedevice with a network connector, and a processing device. The interfaceconnector is disposed at a one edge of the printed circuit board and isconfigured to interface with a mating connector on a server-blade. Theredirection module is configured to receive video signals from a localcomputer of the plurality of local computers through the server-blademating connector. The frame grabber on the printed circuit board grabsscreen frames from the video signals to create screen frame data. Theprocessing device is configured to provide the screen frame data to thenetwork interface device for distribution across a network.

A further aspect of the present invention is a method of controlling aplurality of local computers from a remote computer. A plurality oflocal computers are connected to a corresponding plurality of inputconnectors on a KVM switch. A KVM redirection module is installed in theKVM switch by inserting the module through an opening in a housingsurface of the KVM switch. An interface connector disposed on a firstedge of the redirection module connects to an internal connectordisposed on a surface of a printed circuit board within the KVM switch.A surface of the redirection module that opposes the internal connectoris secured to the housing surface of the KVM switch, holding the modulein place.

A network cable is connected to a network and to a network connector ofthe redirection module. The network connector is externally accessiblethrough an opening in a housing that encompasses the printed circuitboard with the internal connector and the installed redirection module.A local computer is selected from the plurality of local computers.Video signals from the selected local computer are transmitted over thenetwork by the KVM redirection module and received at the remotecomputer. Keyboard or mouse inputs are provided to the local computerfrom the remote computer via the KVM redirection module and KVM switchcombination over the network.

These and various other features as well as advantages, whichcharacterize the present invention, will be apparent from a reading ofthe following detailed description and a review of the associateddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a network operating environment for embodiments ofthe present invention that allow a remote computer to display screenframes of each local computer of a set of local computers and provideuser interaction with the screen frames.

FIG. 2 shows the functional components of a redirection moduleembodiment according to the present invention.

FIG. 3A is a perspective view of a redirection module embodimentaccording to the present invention that is configured to be used withthe KVM switch embodiment of the present invention depicted by FIGS. 4Aand 4B, and with the server-blade embodiment of the present inventiondepicted by FIGS. 5A and 5B, to facilitate the remote management of aset of local computers.

FIG. 3B is a side elevational view of the device embodiment of FIG. 3A.

FIG. 3C is a front elevational view of the device embodiment of FIG. 3A.

FIG. 4A is a perspective view of a system embodiment according to thepresent invention comprising a KVM switch configured for use with aninstalled redirection module of FIG. 3 for remotely managing a set oflocal computers.

FIG. 4B is a rear elevational view of the system of FIG. 4A,illustrating installed redirection modules of FIGS. 3A and 3B, as wellas holes for receiving additional redirection modules and connectors forconnecting the system embodiment to a set of local computers.

FIG. 4C shows the functional components of the system of FIG. 4A.

FIG. 5A is a perspective view of a system embodiment according to thepresent invention comprising a server-blade configured for use with aninstalled redirection module of FIGS. 3A and 3B for remotely managing aset of local computers.

FIG. 5B is a front elevational view of the system of FIG. 5A,illustrating an installed redirection module of FIGS. 3A and 3B.

FIG. 6 is a perspective view of a system embodiment according to thepresent invention comprising a redirection module of FIGS. 3A and 3Binstalled on a development board for testing the redirection module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Local computers may be managed remotely through embodiments of thepresent invention so that the system manager or other user need not bephysically present with the local computer but instead views screendisplays and interacts with the local computer through a remotelylocated computer. For example, the user can remotely view screen framesbeing produced by the local computer to determine whether the localcomputer has crashed or whether the local computer is executing aparticular application. Additionally, the end user may operate a userinput device of the remote computer such as a mouse or keyboard, and theuser input is transferred to the local computer where it can beimplemented.

An environment for application of embodiments of the present inventionis shown in FIG. 1. The environment generally includes a set of localcomputers 102A-102N that are to be remotely managed. Each local computer102 is connected through its video output 108 to an interaction system110. According to one embodiment, interaction system 110 includes a KVMswitch 112 (“switch”) with a KVM redirection module 114 (“module”).System 110, switch 112, and module 114 are described in detail below.

Interaction system 110 is disposed between a network 118 and the set oflocal computers 102A-102N. A remote computer 120 is linked to' thenetwork 118, and the local computer 102 mayor may not be linked to thesame network 118 or another network not shown. The network 118 may be ofvarious forms such as a local area network (“LAN”) or wide area network(“WAN”) including the Internet. A user is located at the remote computer120 and remotely manages the local computer 102 via the network 118 andinteraction system 110.

The interaction system 110 may be linked to the set of local computers102A-102N through several input/output (“I/O”) connections of each localcomputer 102. Generally, a local computer 102 will have a video displayoutput 108, such as an analog or digital VGA output. Also, the localcomputer 102 typically includes a PS/2 port or ordinary serial portconfigured as a mouse port 104, a keyboard port 106, and may also oralternatively include a universal serial bus (“USB”) port (not shown).User input devices may also be provided for each local computer 102,including a local mouse and local keyboard. Conventionally, the localmouse 136 and keyboard 138 would be directly connected to the mouse port104 and keyboard port 106 of the local computer 102. However, in theembodiment shown in FIG. 1, the local mouse 136 and local keyboard 138are connected to a mouse port and keyboard port, respectively, of theinteraction system 110 and provide mouse and keyboard data to theinteraction system 110 through these connections. The interaction system110 then passes the mouse data and keyboard data to the respective portsof the local computer 102.

The video display output 108 provides a signal that ordinarily is passeddirectly to a local display screen 140 or monitor where screen framesare displayed for a user present at the local computer 102. However, inthe embodiment shown, the interaction system 110 provides for thepass-through of the video signal to a local display 140 connecteddirectly to the interaction system 110. In one embodiment, the videodisplay output 108 provides a video signal to a video input of theinteraction system 110. Alternatively, the interaction system 110provides for the pass-through of the video signal back to the localcomputer 102 for output to a local display 140 connected to video output108.

In addition to providing the pass-through of the video signal to a localdisplay screen 140, the interaction system 110 captures screen framedata from the video signal and transfers the screen frame data acrossthe network 118 to the remote computer 120. The remote computer 120 hasa network interface 124 linking the remote computer 120 to the network118. The network interface 124 used by the remote computer 120 may be ofvarious forms such as a dial-up modem or an Ethernet connection to aLAN. Various protocols of data transfer may be utilized between theinteraction device 110 and the remote computer 120, such as the TCP/IPprotocol ordinarily used via the Internet.

The remote computer 120 implements an application, such as a dedicatedapplication or general purpose browser window such as a web browser, forreceiving the screen frame data through the network interface 124 andproviding a display on the display screen 134. The display includes thescreen frame produced by the local computer 102 that corresponds to thescreen frame data transferred by the interaction system 110. Typically,the remote computer 120 includes a video adapter that has a video output128 connected to the display screen 134 to provide the video signals.

To allow the user of the remote computer 120 to fully interact with thelocal computer 102, user interface devices such as a mouse 130 andkeyboard 132 are connected to a mouse port 122 and keyboard port 125,respectively, of the remote computer 120. The user manipulates the mouse130 and keyboard 132 to interact with the screen frame shown on thedisplay screen 134, which may be formed wholly or in part by the screenframe data received over the network 118. When the user activity at theremote computer 120 is entered with respect to the screen frame datareceived from the interaction device, then the processing device of theremote computer 120 transfers the user activity data over the network118 to the interaction device 110 that passes it to the mouse port 104and/or keyboard port 106.

Once the local computer 102 receives the user activity data through themouse port 104 and/or keyboard port 106, the local computer 102 thenimplements the user activity as if it had occurred through a local mouseor local keyboard. When implemented, the user activity alters the screenframe to be displayed. Therefore, the video signal output by the videoconnector 108 to the interaction system 110 provides the screen framesthat show the change caused by the user activity at the remote computer120, such as the mouse pointer moving or letters appearing in anelectronic document.

The interaction system 110 transfers the screen frame data showing theuser activity to the remote computer 120 where it is then provided tothe display screen 134. Thus, the user activity initially performed atthe remote computer 120 is represented on the display screen 134immediately as it is being performed by the user and then once againafter updating the video display of the local computer 102 andtransferring the updated screen frame back to the remote computer 120.

As processing and propagation delays decrease within the environment100, the initial and subsequent display of the same user activity (i.e.,multiple cursors or mouse pointers) on the display screen 134 convergein time so that the user sees only one change. For example, moving amouse pointer within the local computer screen frame shown on thedisplay screen 134 may appear immediately as the user performs theactivity and then later reappear such as a ghost movement once thescreen frame update is received. However, as delays are reduced, forexample by Giga-bit per second network transfer rates, the initial andsubsequent mouse pointer movements converge to one movement as perceivedby the user of the remote computer 120. Furthermore, as discussed below,the display of the local mouse cursor may be turned off for a browserwindow at the remote computer 120 so that only a single mouse cursor isshown at all times, regardless of propagation delays.

In addition to receiving user input, the interaction system 110 may alsoprovide for additional interaction with the remote computer 120 byproviding a USB connection to a USB port (not shown) of the localcomputer. The USB connection allows the interaction system 110 toemulate USB devices for the local computer 102, such as additionalstorage devices including devices that the local computer 102 may usewhen booting-up. For example, the remote computer 120 may provide afloppy, CD-ROM, or hard disk drive that contains a boot-up sequence tobe used by the local computer 102. Upon a connection being establishedover the network 118 between the interaction system 110 and remotecomputer 120, the local computer 102 may boot from a media source of theremote computer 120 with the boot-up sequence provided through the USBport of the local computer.

The USB connection from the interaction system 110 may also allow alocal keyboard and mouse and/or a keyboard and mouse of the remotecomputer to be emulated for the local computer 102. For example, thelocal computer 102 may have only USB ports instead of PS/2 ports and theinteraction system 110 outputs mouse and keyboard signals to the localcomputer through the USB connection.

FIG. 2 shows the major components of one embodiment of the redirectionmodule 114 of FIG. 1. This embodiment of the redirection module 114includes an interface connector 200. This interface connector 200 may bea printed circuit board goldfingers-type connector configured to matewith internal connector 400 of a KVM switch 112 according to anembodiment of the present invention or with 90-degree connector 504 onthe surface of a server-blade 502. Interface connector 200 receivesanalog or digital video signals from a KVM switch 112, as well aspassing and receiving mouse and keyboard commands to and from the KVMswitch 112. All communications between a remote computer 120 and a localcomputer 102 pass through interface connector 200. Redirection module114 may also include an analog to digital converter 204 if used withlocal computers 102 that output analog video signals. The analog VGAsignal includes five distinct signals, including a red drive, a bluedrive, a green drive, a horizontal synchronization pulse, and a verticalsynchronization pulse. In an alternate embodiment, a local displayscreen may be connected to the interaction system 110 for viewing thevideo signal of a local computer 102. In this situation, a video buffer(not shown) may be used to condition the video signal throughamplification and output it to the local display screen so thatsplitting the video signal between the converter 204 and the displayscreen does not degrade the signal and the resulting display.

The converter 204 digitizes the video signal including the five distinctsignals. The converter 204 then outputs the digitized video signal to aframe grabber 206. As one alternative, a digital video output of thelocal computer 102, if available, could be provided to the frame grabber206 in place of the analog video signal that has been digitized asdescribed above. If the local computer 102 provides digital output,digital video signals pass from interface connector 200 to the DVIreceiver 202, which then provides the digital video signals to the framegrabber 206. The frame grabber 206 takes the portion of the digitizedvideo signal corresponding to one screen frame and outputs that portionof the digitized signal as discrete screen frame data. The converter 204and frame grabber 206 may be separate components or may be incorporatedas one component. For example, an LCD controller may be used as a framegrabber 206 to capture the screen frame data.

The screen frame data is utilized by a frame differential component 210to compute a difference between screen frame data of a current screenand a screen frame data of an immediately preceding screen frame. Theframe differential component 210 maintains a previous screen frame datain a first memory location 214 in SDRAM 212 and maintains the currentscreen frame data in a second memory location 216. The framedifferential component 210 then executes an exclusive OR (“XOR”) Booleanoperation upon the two sets of screen frame data to indicate where thechanges have occurred between the two. The result of the XOR operationis stored in a third memory location 218.

The frame differential component 210 provides the screen frame data to aprocessing device 220 so that it may be transmitted. The screen framedata may be either the entire screen frame data of the most currentscreen frame grabbed from the digitized video signal, or may be thescreen frame data making up the difference detected by the XOR operationdescribed above. Providing only the screen frame data representing thedifference between the current screen frame and the preceding screenframe results in less data being distributed over the network 118.

Additional filtering functionality of the frame differential component210 that is applicable when the analog video is digitized to reduce theamount of unnecessary data transfer may also be included, such asapplying threshold comparisons to the most current screen frame data todetermine whether to send the results of the XOR operation or send nonew screen frame data. The threshold of this filtering component may beset as desired. As an example, the filter may look to apply a 7 bit perpixel threshold to determine whether the screen frame data has had asignificant change worth transmitting or only contains sampling noisewhere an analog to digital converter is used. When changes in thecurrent screen frame data are significant as determined by thethreshold, then the result of the XOR may be transmitted. The framedifferential component 210 may be implemented in various ways, includinga programmable logic device such as a field programmable gate array(“FPGA”) 302 or application specific integrated circuit that isconfigured to implement the XOR operations and provide the result to theprocessing device 220.

The processing device 220 interacts with the frame differentialcomponent 210 to access the screen frame data to be provided to anetwork interface device 226. The processing device 220 may beimplemented in various ways discussed above, such as but not limited tothe PowerPC® 405GPr general purpose reduced instruction set processormanufactured by IBM® Corp. The processing device 220 employs logic topackage the screen frame data for transfer by the network device 226 viaa particular protocol, such as TCP/IP. The screen frame data to betransferred may be compressed through anyone of various compressionschemes to further reduce the amount of data to be transferred. Thecompression scheme may be programmed into either the frame differentialcomponent 210 or the processing device 220. Alternatively, the screenframe data may be transferred without being compressed, but additionalnetwork bandwidth will be utilized due to larger data transfers.

The screen frame data may be packaged for distribution by the processingdevice 220 from a network node established by the processing device 220through the network interface 226. As one alternative, the processingdevice 220 in association with the network interface 226 may implementlogic to behave as a web server having a particular IP address for thenetwork 118. This web server service provides the screen frame data as aresource that can be requested by a remote computer 120 through thenetwork 118 by accessing the IP address of the web server service via adedicated or generic browser window, such as a web browser like InternetExplorer by Microsoft®.

The screen frame data may be utilized by the browser window of theremote computer 120 in various ways. As an example, the browser windowmay be used to download the screen frame data in a continuous streamingmanner and the screen frame data may be incorporated for display on thescreen 134 by a dedicated application program of the remote computer120. As another example, the browser window of the remote computer 120may download the screen frame data in a continuous streaming manner fordisplay of the screen frames on the screen 134 within the browser windowitself such as where the browser window is a web browser. The browserwindow may implement browser commands of plug-in logic dedicated for aparticular operating system platform such as an Active X® control todisplay the screen frames, or alternatively may implement a virtualmachine that runs system independent browser commands such as a JAVA™applet.

The processing device 220 interacts with SDRAM 222 to perform theprocessing operations including receiving the screen frame data andpackaging the data for transfer by the network interface 226. Generally,the processing device 220 or network interface includes a media accesscontrol (“MAC”). The MAC obtains carrier access within a network totransmit the packets of the screen frame data and/or browser commandsfor physical layer transfer by the network interface 226. The networkinterface 226 may be of various forms such as a dial-up, digitalsubscriber line, ISDN, or cable modem or an Ethernet transceiverdirectly linked to a data network. The data is transferred from thetransceiver of the network interface 226 via the network 118 to theappropriate IP address of the network interface 124 of the remotecomputer 120.

In addition to transferring the screen data to the remote computer 120via the network 118, the network interface 226 also receives datatransferred from the remote computer 120 over the network 118. Thenetwork interface 226 receives the request for screen frame data thatoccurs once the remote computer's browser has been directed to the IFaddress of the web server service associated with the redirection module114. An example of a network interface 226 is a “phy” such as modelLXT972A manufactured by Intel® Corp.

Additionally, the network interface 226 may receive data from the remotecomputer 120 that is indicative of the user activity occurring on theuser interface devices of the remote computer 120. As discussed above,the end user may interact with the local computer screen frame beingdisplayed on the screen 134 of the remote computer 120 by using themouse and keyboard when the focus of the remote computer 120 is withinthe browser window display. The browser commands receive the user inputof the user interface device and generate data corresponding to the userinput relative to the local computer screen frame. The data istransmitted to the redirection module 114.

The redirection module 114 receives the data indicating the useractivity through the network interface 226 where it is unpackaged fromits transmitted state back to data that can be interpreted by theprocessing device 220. The processing device 220 receives the datadescribing the user activity that took place through the user interfacedevices of the remote computer 102. The processing device 220 thenoutputs a user interface command to a microcontroller 228. In alternateembodiments, a local keyboard and local mouse (not shown) may beconnected to the interaction system 110 or a local computer 102. Inthese embodiments, the microcontroller 228 arbitrates between the userinput received over the network and the local user input receivedthrough a bus connection to an 80C42 compatible keyboard/mousecontroller (not shown) that is coupled to the local mouse and keyboard.The microcontroller 228 may arbitrate by giving priority to one of theinputs where both the local and remote user input is receivedsimultaneously to produce a clock and data output that is sent to themouse or keyboard port of the local computer 102. In many instances, itmay be appropriate to give the user input received over the networkconnection priority over local user inputs.

The local computer 102 implements the user activities transferred to theinteraction device 110 over the network 118 as if they occurred throughuser interface devices directly coupled to the interface system 110 orlocal computer 102. The user interface data provided as signals from themicrocontroller 228 to the mouse port 104 or keyboard port 106 of thelocal computer 102 appear as ordinary mouse and keyboard data and clocksignals. Flash interface 230 may store an operating system as well asprovide a flash file system. A recovery switch (not shown) allows a userto recover from a firmware upgrade where the upgrade process failed orwas interrupted. Normally, a firmware upgrade is done over the network118 through the network connector. If the connection is lost during anupgrade, the firmware image may be corrupted. The recovery switch may beheld in at power-up, allowing the redirection module 114 to enter aprotected boot block of code in flash 230 that is never overwrittenduring a firmware upgrade.

RS-232 port 240 provides an interface for connecting the redirectionmodule 114 to a serial port of the local computer 102. A cable (notshown) may be provided with the redirection module 114 that has aconnector for port 240 on one end and a standard DB-9 connector for aserial port on local computer 102. Port 240 may be used for debugging,diagnostics, and firmware upgrades. Additionally, a user may connect theredirection module 114 to a serial port of the local computer 102 usingport 240 and associated cable, and use a terminal program to configurenetwork settings, such as DCHP or static IP address, netmasks, andgateways. Port 240 communicates with processor 220 through RS-232 levelshifters 238.

RS-232 port 242 may also be connected to a number of readily availablepower switches, which can be used to control power on and off to one ormultiple servers. Using port 242, a remote user may cycle power onanyone local computer of the set of local computers 102A-102N by issuinga command through the network 118, which is transmitted through networkinterface 226, to processor 220, to level shifters 238, to the port 240,and subsequently to the power switch (not shown). Real time clock(“RTC”) 232 provides for timekeeping functions, allowing for storage oftimes associated with certain events, such as keeping a log detailingwhen each user logs in and out.

To establish the USB connectivity discussed above between theinteraction system 110 and the local computer 102, a USB microcontroller234 may be included. The USB microcontroller 234 communicates with theprocessing device 220 to emulate a USB node for the local computer 102.Thus, a media source of the remote computer may be accessible by thelocal computer 102 by the USB microcontroller 234 emulating a USB mediadevice for the local computer 102. Also, as discussed above, the USBmicrocontroller 234 may allow the emulation of a keyboard and mouse forthe USB input of the local computer 102 to pass local and/or remotekeyboard and mouse signals to the local computer 102.

FIGS. 3A and 3B show a perspective view and side elevational view,respectively, of a redirection module 114 according to aspects of thepresent invention. Redirection module 114 consists of printed circuitboard (“PCB”) 300. PCB 300 contains and electrically connects thehardware necessary for managing and controlling a local computer 102from a remote computer 120. The module 114 is configured for use with aKVM switch 112 that connects to a plurality of local computers102A-102N. The KVM switch 112 allows for the remote monitoring andmanagement of multiple computers 102A-102N one at a time, using a singleredirection module 114, or simultaneous monitoring and management of oneor more computer 102A-102N using multiple redirection modules 114. TheKVM switch 112 is described in detail below with reference to FIGS. 4Aand 4B.

Interface connector 200 provides the interface between redirectionmodule 114 and KVM switch 112 or server-blade 502. Interface connector200 is preferably a PCB goldfingers-type connector. It is to beunderstood by one skilled in the art that any other type of connectornow known or developed in the future that is suitable forcommunicatively connecting the components of redirection module 114 tothe components of switch 112 or server-blade 502 may be used.Redirection module 114 further comprises analog-to-digital-converter204, field programmable gate array 302, processor 220, flash interface230, USB microcontroller 234, network interface 226, and RS-232 ports240 and 242 as described above. As stated above, the converter 204 mayincorporate an LCD controller to be used as a frame grabber 206 tocapture the screen frame data. FPGA 302 provides the functionality ofthe frame differential component 210 described above.

Redirection module 114 also contains RTC battery 304 for providingbattery power to the RTC 232, and also connectors 312 and 314. Connector312 may be used to connect an in-circuit emulator to the processor 220and for programming flash interface 230. Similarly, connector 314 may beused for programming firmware for the PS/2 microcontroller 228. Module114 is configured to easily install vertically into KVM switch 112 orhorizontally onto server-blade 502. As seen in FIGS. 3A and 3B, thedistance between opposing sides of module 114 is represented by heighth. The maximum height h should allow the module 114 to installvertically in a 1 U, or 1.75 inch, height KVM switch 112. Preferably,the height h of module 114 should be equal to or less than 1.625 inches.For installation on a server-blade, as shown in FIGS. 5A and 5B anddiscussed below, module 114 has connectors 310. Fasteners 310 extendthrough PCB 300 to secure module 114 in a horizontal position onserver-blade 502. As will be appreciated by those skilled in the art,fasteners 310 may be screws or any other type of re-usable fastenersuitable for securing and unsecuring module 114 to and from server-blade502. Various power sources may be included for the module 114. On-boardbatteries and/or a wall adapter may be utilized to provide the DCvoltage required by the circuitry described above. Preferably, themodule 114 may draw power from its connection to the KVM switch 112,through the interface connector 200.

As seen in FIGS. 3A and 3C, module 114 has a front surface 306, which isdisposed on the end of module 114 opposite of the interface connector200. Front surface 306 provides a mounting surface for securing module114 to a KVM switch 112. Fastener 308 protrudes through front surface306 and secures front surface 306 to a vertical surface of switch 112.It is to be appreciated that fastener 308 may be a screw, clip, or anyother type of re-usable fastener suitable for securing and unsecuringmodule 114 to and from switch 112. Front surface 306 provides aperturesthrough which network interface 226, and RS-232 ports 240 and 242protrude. In this manner, network connections may be made to thesecomponents while redirection module is installed in KVM switch 112.

Additionally, LEDs 316 are provided on front surface 306 as indicationsthat the module 114 is powered and operational. It is to be understoodthat any type, color, or number of LEDs may be used to provide any typeof status indication, including other types of visual or audible statusindicators to provide a user with component status indications whilemodule 114 is installed in switch 112. FIGS. 3A and 3C also show resetbutton 318, which is a recessed micro-tactile switch that can bedepressed in the event of a catastrophic error to reset module 114without the necessity of cycling the power. Although reset button 318 isrecessed to prevent accidental depression, it may also be a raisedbutton or a toggle switch.

FIG. 4A shows a perspective view of interaction system 110. FIG. 4Bshows a rear view of KVM switch 112. Interaction system 110 comprisesKVM switch 112 and redirection module 114. A typical KVM switch is usedto enable a user to monitor and control a set of local computers102A-102N, one at a time, using a single keyboard, mouse, and monitorconnected to the KVM switch. Each local computer of the set of localcomputers 102A-102N is connected to the KVM switch through a connector404. A local display monitor 140 may be connected to switch 112 usingVGA connector 410. A local mouse and keyboard may be connected to switch112 using PS/2 connectors 416 and 414, respectively. Alternatively, USBconnectors may be used in place of PS/2 connectors 416 and 414 and a DVIconnector may replace video connector 410. Power port 412 is suppliedfor connection to a power source. It is desirable for a user to be ableto monitor and interact with the local computers 102A-102N from a remotelocation, rather than having to be at the KVM switch. To do so,redirection module 114 is required.

FIG. 4B shows a KVM switch 112 with multiple redirection modules 114installed. It is to be understood that switch 112 may be configured fora single redirection module 114 or multiple modules. Only a singlemodule 114 is required for a single user to be able to remotely controla single computer 102 of a set of local computers 102A-102N. Switch 112allows the remote user to switch between local computers 102A-102N formonitoring and interaction. This switching functionality will bedescribed below in reference to FIG. 4C. If it is desired that multipleusers at multiple remote computers be able to remotely monitor andinteract with computers 102A-102N simultaneously, then multiple modules114 are required. For each module 114 installed, a separate user maymonitor and interact with the same local computer 102 or different localcomputers at the same time.

As seen in FIG. 4B, KVM switch 112 contains at least one opening 406 forreceiving a redirection module 114. It is to be understood that theswitch 112 may contain one opening 406 per module 114 that the switch isconfigured to receive, or the switch may contain a single openingthrough which all modules are installed. A blank 408 may be installed inany opening 406 that does not contain an installed redirection module.Redirection module 114 and KVM switch 112 are designed with hot-swappingcapability. That is, the module 114 may be installed into anduninstalled from KVM switch 112 while the switch is powered on andoperating.

Switch 112 includes internal connector 400 connected to a PCB. Internalconnector 400 must be capable of transferring communications between aPCB of switch 112 and goldfingers interface connector 200. Preferably,vertical connector 15-92-1440 from MOLEX, INC. is used. Internalconnector 400 is mounted within switch 112 opposite opening 406.Interface connector 200 of module 114 is fully seated within connector400 when the module is slid through opening 406 of switch 112 and intothe switch until the front surface 306 of the module is flush againstsurface 402 of the KVM switch. To facilitate installation of redirectionmodule 114 into KVM switch 112, slide rails 440 may be used or slotswithin the KVM switch housing for guiding the edges of redirectionmodule 114. Fastener 308 may be used to secure the front surface 306 ofthe module 114 to surface 402 of the switch 112. As discussed above, oneskilled in the art will appreciate that other securing means may beused.

FIG. 4C shows the functional components of the interaction system 110and illustrates the capabilities of system 110 to monitor and interactwith each local computer 102A-102N, one at a time, using remote inputfrom mouse 130 and keyboard 132, as well as local input from mouse 136and keyboard 138. FIG. 4C has been simplified for the purposes ofillustration. According to FIG. 4C, interaction system 110 providesmonitoring and interaction capabilities for only two local computers,102A and 102B; however, it is to be understood that any number of localcomputers 102A-102N may be connected to interaction system 110, subjectonly to the number of connectors 404 that switch 112 may physicallyaccommodate.

Video signals from local computer 102A enter interaction system 110 andenter the video switch matrix 418. If a user has selected local computer102A for monitoring, the signals will pass through the video switchmatrix 418 to the amplifier buffer 420. The signals then pass to a localdisplay screen 140. Local display screen 140 is connected to the KVMswitch 112 through video connector 410. The video signal is also passedthrough resistor 422 to redirection module 114 where it is processed totransfer captured screen frame data through a network to a remotecomputer as described above. When mouse and keyboard data is input fromthe remote computer and passed through the network to the redirectionmodule 114, the data is transferred to a mouse and keyboard switch 424.

At switch 424, arbitration occurs between mouse and keyboard input fromthe remote computer and conflicting mouse and keyboard input from localmouse 136 and keyboard 138. For example, when mouse and keyboard inputis entering interaction system 110 from both the remote computer andlocal mouse and keyboard at the same time, it may be desirable for thelocal mouse and keyboard input to control. With this rule programmedinto switch 424, or when switch 424 is otherwise instructed by processor220 or other component, the switch 424 will only allow local mouse andkeyboard commands to pass to the switch matrix 428 when in directconflict with input from the mouse and keyboard attached to the remotecomputer. If a user has selected local computer 102A for monitoring, thesignals will pass through the keyboard/mouse switch matrix 428 to localcomputer 102A. Microcontroller 436 returns a mouse response for localcomputer 102B when queried by the local computer when the local computeris powered on. By doing so, local computer 102B will believe that amouse is connected to the computer and will recognize and accept theremote mouse input when the keyboard/mouse switch matrix 428 switchesfrom local computer 102A to local computer 102B.

When a user chooses to monitor and interact with a different localcomputer from the computer currently being monitored, the change mayoccur in one of two ways. First, if interacting with the local computer102A from a local computer directly connected to interaction system 110,the user may press button 432. Button 432 activates a switch within portselector 430, which causes the video switch matrix 418 andkeyboard/mouse switch matrix 428 to activate internal switches that willdeselect computer 102A and select 102B in a manner well known to thosewell skilled in the art. It is to be understood that while port selector430, video switch matrix 418, and keyboard/mouse switch matrix 428 aredepicted in FIG. 4C as three separate components, they may be a singlecomponent or multiple components.

If a user is interacting with the local computer 102A from a remotelocation over a network and wishes to select local computer 102B formonitoring and interaction, the user may make the selection using amouse, a button, a typed command, or by executing a predetermined keycombination. Interaction system 110 may be programmed to recognize thecommand from the remote computer as a selection of a different localcomputer for monitoring. The command will be passed through thekeyboard/mouse switch matrix 428 to port selector 430 via pathway 434.The command will electrically activate port selector 430 just as ifbutton 432 had been physically pressed.

FIGS. 5A and 5B depict an alternate embodiment of the present invention,interaction system 500. With interaction system 500, a redirectionmodule 114 is used with a server-blade 502 to allow a user to remotelymonitor and manage the server-blade. Video and control inputs are passedto and from server-blade 502 and a remote computer 120 using redirectionmodule 114, just as redirection module 114 and KVM switch 112 may beused to pass video and control inputs to and from a set of localcomputers and a remote computer as described above. Redirection module114 is mounted in a horizontal configuration as seen in FIG. 5A using amating connector 504.

Mating connector 504 is preferably right-angle connector 87620-0001 fromMOLEX, INC., but may be any connector suitable for transferringcommunications between server-blade 502 and goldfingers interfaceconnector 200. When mounted in a horizontal configuration, as seen inFIGS. 5A and 5B, redirection module 114 may be secured to theserver-blade 502 using fasteners 310. While FIG. 3B shows two fasteners310, any number and type of fasteners may be used. Additionally, spacers508 may be used between server-blade 502 and module 114 to secure themodule in a horizontal position with a desired distance between themodule and the server-blade, depending on the height of the matingconnector 504. This can be seen in FIG. 5B, which shows a frontelevational view of the redirection module 114 mounted on a server-blade502, which is mounted in a rack 506.

The dimensions of module 114 preferably remain the same as describedabove with respect to FIGS. 3A and 3B. Because of the minimal size ofredirection module 114 and the horizontal mounting configuration, thedistance d as measured from the top of the server-blade to the top offront surface 306 is minimized. Preferably, distance d is less than oneinch. This mounting configuration is advantageous since it allows anumber of server-blades 502 to be rack-mounted very close together,while providing the remote management capabilities of the redirectionmodule 114. By mounting the module 114 in a position spaced aboveserver-blade 502, the board space below the module is still availablefor circuitry and other components. In other words, module 114 takes upvery little space on server-blade 502. As with the KVM switch 112, theredirection module 114 and server-blade 502 are configured such that themodule may be hot-swapped without removing power from the server-blade.In another embodiment, redirection module 114 may be installed on amaster server-blade that has switching capabilities and is connected toa set of server-blades. The master blade acts in a capacity similar tothe KVM switch 112 described above.

FIG. 6 illustrates a further embodiment of the present invention.Interaction system 600 includes a redirection module 114 coupled with adevelopment board 602. Development board 602 includes video connector610 and PS/2 ports 612 and 614 for connection to local display,keyboard, and mouse. Board 602 also includes DVI video input 608 and VGAinput 604 for connecting the board to local computers. RS-232 serialport 606 is used for debugging and development. Power may be supplied tointeraction system 600 through power supply jack 616. Port 618 providesa mini-USB type connector for connection to a host PCB. Interactionsystem 600 may be shipped to customers for testing of redirection module114 as well as for development of firmware for the module. It provides aquick, simple method of testing redirection module 114 with currentsystems.

A method of controlling a plurality of local computers 102A-102N from aremote computer 120 when a user connects a set of local computers102A-102N to the KVM switch 112. The connections are made using cablesfrom each computer 102 to a input connector 404 of the switch 112. Theuser then installs a KVM redirection module 114 into switch 112 byremoving blank 408, sliding the module through opening 406 until thefront surface 306 of the module is flush against surface 402 of theswitch, and securing the module to the switch using fastener 308. Theuser plugs one end of a network cable into network interface 226, andthe other end to a network 118. After these steps are completed, remotemonitoring and interaction is possible. It is to be understood thatthese steps can be performed in any order and are not limited to theorder discussed here.

The user then selects a local computer for monitoring at select step 708by issuing commands to the KVM switch 112 from the remote computer 120.If more than one module 114 is installed in switch 112, the user maymonitor more than one computer 102 simultaneously. The user receives andviews video signals from the selected local computer 102 at the displayscreen 134 of the remote computer 120. The user can use a mouse 130 andkeyboard 132 at the remote computer 120 to provide input to and interactwith local computer 102. This input is transmitted over the network 118to the local computer 102.

Although the present invention has been described in connection withvarious illustrative embodiments, those of ordinary skill in the artwill understand that many modifications can be made thereto within thescope of the claims that follow. Accordingly, it is not intended thatthe scope of the invention in any way be limited by the abovedescription, but instead be determined entirely by reference to theclaims that follow.

1. A keyboard, video, mouse (KVM) switch for allowing control of a plurality of local computers from a remote computer, comprising: a printed circuit board having at least one internal connector for connection to a KVM redirection module, wherein the at least one internal connector is configured to provide video signal data from a local computer of the plurality of local computers to a connected KVM redirection module; a housing that encloses the printed circuit board and at least one internal connector comprising at least one opening corresponding to the at least one internal connector for receiving a KVM redirection module; a plurality of keyboard, video, and mouse input connectors electrically connected to the printed circuit board corresponding to the plurality of local computers, wherein the plurality of keyboard, video, and mouse input connectors are accessible externally from the housing; and means for selecting a local computer from the plurality of local computers for controlling with the remote computer.
 2. The KVM switch of claim 1, wherein the housing further comprises: a first vertical surface parallel to and opposing the printed circuit board, wherein the at least one opening is through the first vertical surface at a location opposing the at least one internal connector; guiding means for slidably receiving a KVM redirection module such that a connector on one end of the module engages the internal connector on the printed circuit board while a face surface of the module contacts the first vertical surface of the housing.
 3. The KVM switch of claim 2, wherein the guiding means comprises slide rails disposed within the housing substantially perpendicular to the first vertical surface.
 4. The KVM switch of claim 1, wherein the KVM switch housing has a height dimension equal to or less than 1U.
 5. The KVM switch of claim 1, wherein the switch is configured to allow a KVM redirection module to be inserted through the at least one opening and connected to the at least one internal connector to begin operation of the module without removing power from the switch. 